Lubricants



Patented Dec. 30, 1941 LUBRICANTS Eugene Lieber, Linden, N. 1., assignor to Standard Oil Development Company, a. corporation of Delaware No Drawing.

Application September 20, 1938,

Serial No. 230,813

14 Claims.

The present invention relates to improved lubrlcants and more especially to waxy lubricating oils containing pour point depressants of a new type. The invention will be fully understood from the following description.

It has been found that superior pour point depressants and thickeners can be produced by the condensation of the acid halides, obtained from polycarboxylic acids, with mineral oils. Heretofore acid halides have been condensed with aromatic compounds, but such materials as a rule are not usefulas pour depressants. They also have certain other disadvantages which are well known to those skilled in the art. It has been discovered that the present depressants and thickeners made by the condensation of halides of polycarboxylic acids with petroleum oils, especially with lubricating oils or extraction products thereof, are particularly advantageous. They may be made from all types of lubricating oils whether obtained from naphthenic, asphaltic or paraflinic groups, and are made from the residual as well as distillate oils and even from low boiling distillates such as gas oils and kerosene, boiling above the gasoline range.

When making these materials from distillate oils, there is little difficulty encountered, but when using residual oils, it is sometimes necessary to purify the oil before condensation in order to remove sludge, asphaltic and other very heavy molecular weight compounds. This can be done by precipitation thereof with various asphalt precipitating agents. The best of this class of substances are the low specific gravity naphtha fractions and the liquefied, normally gaseous hydrocarbons such as ethane, propane, butane and various-mixtures of these compounds. The precipitation may be accomplished under of materials satisfactory for the present purpose,

and that other halides, especially bromides may be employed, as well as halides of other acids.

The reaction is carried out under the influence of catalysts, preferably those of the Friedel- Crafts type such as aluminum chloride, zinc chloride, boron fluoride, titanium chloride or fluoride and their various known equivalents. It is generally desirable to employ a solvent such as a naphtha or an inert halogented solvent such as tri or tetrachlor ethane, carbon disulfide or the like. The di-acyl halide and the petroleum oil fractions may vary considerably in proportions, but it has been found that best results for producing pour depressing compounds are obtained where 100 parts by weight of the petroleum oil are used with from about 5 to 30 parts of the acid halide. Similarly the amount of catalyst may also vary, but it is usually desirable to employ at least one mol of aluminum chloride or other catalyst for each mol of the dicarboxylic acid halide employed. The amount of catalyst may be increased above this amount if desired, in order to increase the reaction and to make it proceed more smoothly.

The reaction time is dependent on the proportion of ingredients and the amount of catalyst, as well as on the specific halide and oil employed, but in general reaction time is from /2 to 4 or 5 hours. At room temperature, at which most of the halides react quite vigorously, a reaction time of an hour or two is usually suflicient and at more elevated temperatures, for example up to about 200", F., the reaction is quite rapid. In

well known conditions either by reducing the temperature or by raising the temperature to the vicinity (above or below) of the critical point of the precipitant. Under the higher temperature process, it is necessary for the oils to be maintained under high pressure so as to maintain them in liquid condition. If the temperature is raised to above the critical temperature of the precipitant, a suflicient solution thereof in the oils or in a solvent added for the purpose is obtained to effect precipitation. In either case, the asphaltic and heavier compounds are precipitated and the purified oil may be separated either by decantation or filtration.

The acid halides used for the present purpose are preferably acid chlorides obtained fr'oin'di carboxylic acids which may be either aliphatic or aromatic. Among the diacyl halides that have been employed may be mentioned the acid chlorides of sebacic, succinic, adipic, oxalic and phthallc acids, but it will be understood that these are only examples to illustrate the type many instances, the reaction is so vigorous that no heating whatever is required. Temperature and time of reaction are preferably adjusted so as to avoid the formation of solid, rubbery, insoluble, carbonaceous materials.

At the end of the reaction period, the mixture is preferably diluted with kerosene and then admixed with a relatively large volume of alcohol and water. Catalytic sludge is thus hydrolyzed and the kerosene layer, containing the desired products, may be decanted from the aqueous sludge layer. The depressant is recovered by distilling the kerosene and other diluent and is collected as the distillation residue.

The product produced as above is a viscous oily material of good appearance. It is stable and freely soluble in lubricating oils. The proportions employed for pour depression. depend to some extent on the particular material and the conditions under which it is produced, and also on the nature of the oil to which it isadded. However, the proportions are ordinarily from about /2 to 5% in order to produce a marked pour depression.

In producing products which are to be used principally as thickening agents, it is most desirgrams of sebacic acid were mixed with grams of phosphorous trichloride and heated on a water bath. When reaction was complete, the

sebacyl chloride which has the formula ClOC-(CHz) s--COC1 was decanted off of the phosphorous acid solution and was mixed with 100 grams of Pennsylvania Bright stock. This mixture was then dissolved in 200 cc. of tetrachlor ethane and 14 grams of anhydrous aluminum chloride were slo'wly added to the mixture which was maintained at room temperature while agitating. A

.vigorous reaction took place and hydrochloric acid gas was rapidly evolved. The catalystwas added over a period of about one hour and after the addition thereof the reaction was warmed on the water bath'to about 80 C. for an additional period of 30 minutes. v At the end of this period the mixture was diluted with 1,000 cc. of kerosene and poured into a large volume of the alcohol and water. The kerosene layer was decanted from the aqueous layer and was distilled with fire and steam to 600 F. in order to remove the solvent, kerosene and the lower boiling fractions of the condensation product. In this manner, a residue amounting to 96 grams was obtained.

The original Pennsylvania oil had a viscosity of 143 sec. Saybolt at 210 and the recovered condensation product had a viscosity of 533 sec. at

When 5% of the condensation product was added to a waxy mineral oil, the original pour point of +30 F. was reduced to -20 F.

Example II Another pour depressant was made using the same procedure as in Example I, except that the reagents were changed as follows:

Pennsylvania Bright stock grams 150 Tetrachlorethane cc 300 Sebacic acid grams 30 Phosphorous trichloride do A1013 do 81 Under these conditions the yield was 142 grams of an extremely viscous oil. The original lubricating oil used in this experiment had a viscosity of 153 sec. Saybolt at 210 F.; the condensation product had a viscosity of 4190.

When 5% of this condensation product was added to a waxy lubricating oil having a pour point of +30 F., it was found to be reduced to 10 F.

' Example III 15 grams of adipic acid were mixed with 15 grams of phosphorous trichloride on the water bath. The adipyl chloride was then collected just as described in Example I and to the total amount of adipyl chloride collected were added grams of Pennsylvania Bright stock and 300 grams of tetrachlor ethane for use as a solvent. This mixture was put into a three liter flask which was provided with a stirring rod and an outlet for gaseous reaction products. 60 grams of AlCls were then added slowly so the temperature was maintained at 80 F. for a period of one hour. It was then cooled to room temperature and maintained for an hour longer. It was then heated to between F. and F. for two hours and diluted with 1,000 cc. of kerosene. This mixture was then poured into a large volume of alcohol and water as in Example I and 100 grams of a viscous oil were obtained on distilling the kerosene layer. The product had a viscosity of .4169 sec. Saybolt at 210 F., and on addition of 5% thereof to an oil having an original pour point of 30 F., it was found that the pour point was reduced to 10 F.

Example IV Experiment 3 was repeated except that 30 grams of A1C13 were used and 100 grams of a viscous oily product having a viscosity of 888 sec. at 210 were collected. This material when 5% was added to an oil having a pour point of +30 F., produced a reduction to 0 F.

Example V dissolved in cc. of tetrachlorethane as solvent. 28 grams of AICI: was slowly added to this mixture 'at room temperature and no attempt was made to cool the reaction mixture. Very vigorous reaction took place as evidenced by the evolution of hydrogen chloride gas. Thirty minutes were required to add the AlCls. After the addition of the AlCla, the reaction mixture was heated to 90 C. and maintained thereat with stirring for 60 minutes. .The reaction mixture was then neutralized as described in Example I. The kerosene extract was distilled with fireand steam to 600 F. to remove low boiling materials. 69 grams of a heavy green oil was obtained.

The original Columbian gas oil had a viscosity of 50 sec. Saybolt at 100 F. and the recovered condensation product had a viscosity of 210 sec.

Saybolt at 210 F.

Another pour depressor was made using the same procedure as in Example V, except that the reagents were changed as follows:

- Grams Columbian gas oil r 200 Sebacic, acid 40 After recovery and removal of low boiling products, 103 grams of a viscous residue was obtained.

When 5% of this condensation product was added to a waxy lubricating oil having a pour point of +30 F., it was found to be reduced to Example VII The following example will illustrate the prepa- 4 ration of a pour depressor from a total distillate lubricating oil of comparatively low viscosity. The total distillate lubricating oil used was a spindle oil.

The experimental procedure of Example V was followed exactly except that the following reagents were used:

Grams Spindle oil 200 Sebacic acid 20 A1013 28 sation product was tested by blending in a wax-' bearing oil. The following data was obtained:

' Pour point, F.

Waxy-oil +30 Waxy-oil 1% condensation product +20 Waxy-oil 2% condensation product.. +5 Waxy-oil 5% condensation product Example VII The following example will illustrate the preparations of pour depressors from kerosene.

The experimental procedure of Example V was followed exactly except that the following reagents were used:

Grams Kerosene (aniline point, 35 F.) 200 Sebacic acid AlCl; 28

After recovery and removal of low boiling products, 48 grams of a green viscous oil was obtained.

When 5% of the condensation product was added to a waxy mineral oil, the original pour point of +30 F. was reduced to 0, F.

Example IX The oil thickening and V. I. improving properties of the products of my invention is illustrated by the following example.

The condensation product of Example II having a viscosity of 4190 sec. Saybolt at 210 F. was blended intoa spindle oil and the change in V. I. noted. As a comparison, the original Penn. Bright stock was also tested. The following results were obtained.

Saybolt sec.

Vis./l00 Vis./2l0 V. I.

Spindle oil 149 42. 8 100 Spindle oil+5% Penn Bright stock. 170 44. 3 97 Spindle oil+5% condensation product. 246 50. 6 133 The present products can be used as wax modifiers for various purposes, for example, to assist in separation of wax from oils by filtration, s'ettling and centrifugation of diluted oil which is chilled to the wax precipitation point. Small 7 amounts of the modifier greatly increase ease of separation.

The present invention is not to be limited by any theory of the mechanism of the reaction nor to any particular reagents or catalysts, but only to the following claims in which it is desired to claim all novelty inherent in the invention.

I claim:

1. Composition of matter comprising a mineral oil and a small proportion of a condensation product of a polycarboxylic acid halide and a petroleum oil fraction.

2. Composition of matter comprising a mineral oil ,and a small proportion of a condensation product of polycarboxylic acid halide and a petroleum oil boiling above the gasoline range.

3. Composition of matter comprising a mineral oil and a condensation product of a dicarboxylic acid halide and a petroleum lubricating oil.

4. Composition of matter comprising a lubricating oil and a condensation product of a dicarboxylic acid halide and a petroleum oil, the condensation product being obtained by condensation of 5 to 30 parts of the said dicarboxylic acid halide to parts of the mineral oil.

5. Composition according to claim 4 in which an aliphatic dicarboxylic acid chloride and a residual petroleum oil are used.

6. Product according to claim 4 in which an oil of the type of Bright stock is employed in producing the condensation product.

7. Product according to claim 4 in which the condensation product is produced from sebacic acid chloride and a residual lubricating oil.

8. Product according to claim 4 in which the condensation product is produced from adipic acid chloride and a residual petroleum oil.

9. Lubricating oil of low pour point comprising a waxy lubricating oil and a product obtained by the condensationof a dicarboxylic acid halide with a petroleum oil boiling above the gasoline range.

10. Product according to claim 9 in which the condensation product is obtained by condensation of from 5 to 30 parts of the poly-acid halide to 100 parts of the mineral lubricating oil.

11. Product according to claim 9 in which the condensation product is obtained by condensation of from 5 to 30 parts of an aliphatic dicarboxylic chloride and 100 parts of a residual lubrieating oil.

12. A composition comprising a major proportion of a lubricating oil base stock and a minor proportion of a condensation product of a carboxylic acid halide having the general formula C1OC(CH2)n-COC1, where n is zero to 8, and a petroleum oil boiling above the gasoline range.

13. A composition comprising a major proportion of mineral lubricating oil base stock and a minor proportion of a viscous, oily, oil-soluble condensation product of sebacyl chloride and Pennsylvania Bright stock, said condensation product being obtained by condensation of 5 to 30 parts of said sebacyl chloride to 100 parts of Bright stock, in the presence of tetrachlorethane, using aluminum chloride as condensing catalyst, at a temperature between about room temperature and about 200 F.

14. A composition comprising a major proportion of waxy mineral lubricating oil base stocks and a minor proportion of an oil-soluble condensation product obtained by a Friedel-Crafts condensation of about 5 to 30 parts of dicarboxylic acid chloride having the general formula ClOC-(CH2)COC1, where n is zero to 8, and 100 parts of a petroleum oil boiling above the gasoline range, at a temperature between about room temperature and about 200 F., for a period of about to 5 hours, using at least about 1 mol of aluminum chloride to 1 mol of the acid Gil halide, stopping the reaction before formation of insoluble solid rubbery products, diluting the reaction product with kerosene, hydrolyzing and removing residual catalyst, and distilling the reaction product mixture by fire and steam to about 600 F. to'obtain the desired residue.

' EUGENE LIEBER. 

